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@bellbind
Created October 23, 2009 10:57
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[WebGL] Texture example by img tag
<!DOCTYPE html>
<html>
<head>
<script>//<!--
// WebGL texture example
top.CanvasFloatArray = top.CanvasFloatArray || WebGLFloatArray;
var gl;
var program;
var start = function () {
var canvas = document.getElementById("canvas");
try {
gl = canvas.getContext("webkit-3d");
} catch (ex) {
gl = canvas.getContext("moz-webgl");
}
gl.clearColor(0.0, 0.0, 0.0, 1.0);
if (gl.clearDepth) gl.clearDepth(1.0); else gl.clearDepthf(1.0);
gl.enable(gl.DEPTH_TEST);
gl.enable(gl.TEXTURING);
gl.enable(gl.TEXTURE_2D);
updateShaders();
initTexture();
render();
setInterval(render, 100);
};
var updateShaders = function () {
var vs = gl.createShader(gl.VERTEX_SHADER);
var vsSource = document.getElementById("vs").value;
gl.shaderSource(vs, vsSource);
gl.compileShader(vs);
//if (!gl.getShaderi(vs, gl.COMPILE_STATUS)) {
// alert(gl.getShaderInfoLog(vs));
//}
var fs = gl.createShader(gl.FRAGMENT_SHADER);
var fsSource = document.getElementById("fs").value;
gl.shaderSource(fs, fsSource);
gl.compileShader(fs);
//if (!gl.getShaderi(fs, gl.COMPILE_STATUS)) {
// alert(gl.getShaderInfoLog(fs));
//}
program = gl.createProgram();
gl.attachShader(program, vs);
gl.attachShader(program, fs);
gl.linkProgram(program);
//if (!gl.getProgrami(program, gl.LINK_STATUS)) {
// alert(gl.getProgramInfoLog(program));
//}
gl.useProgram(program);
};
var initTexture = function () {
var textureImg = document.getElementById("texture");
var texture = gl.createTexture();
gl.activeTexture(gl.TEXTURE0);
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texImage2D(gl.TEXTURE_2D, 0, textureImg);
gl.generateMipmap(gl.TEXTURE_2D);
};
var render = function () {
var verts = [
-0.5, -0.5, 0.0,
0.5, -0.5, 0.0,
0.5, 0.5, 0.0,
-0.5, -0.5, 0.0,
0.5, 0.5, 0.0,
-0.5, 0.5, 0.0,
];
var buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, new CanvasFloatArray(verts), gl.STATIC_DRAW);
var position = gl.getAttribLocation(program, "position");
gl.vertexAttribPointer(position, 3, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(position);
var texCoordData = [
0.0, 0.01,
1.0, 0.01,
1.0, 1.0,
0.0, 0.01,
1.0, 1.0,
0.0, 1.0,
];
var tbuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, tbuffer);
gl.bufferData(
gl.ARRAY_BUFFER, new CanvasFloatArray(texCoordData), gl.STATIC_DRAW);
var texCoord = gl.getAttribLocation(program, "coord");
gl.vertexAttribPointer(texCoord, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(texCoord);
var texture0 = gl.getUniformLocation(program, "texture0");
gl.uniform1i(texture0, 0);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.drawArrays(gl.TRIANGLES, 0, verts.length / 3);
};
//--></script>
</head>
<body onload="start()">
<div>
<canvas id="canvas" style="width: 300px; height: 300px;" />
</div>
<div>
<img id="texture"
src="data:img/png;base64,iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAYAAACqaXHeAAAAAXNSR0IArs4c6QAAAAlwSFlzAAAL
EwAACxMBAJqcGAAAAAd0SU1FB9kKFwIVMoJ98zoAAAAZdEVYdENvbW1lbnQAQ3JlYXRlZCB3aXRo
IEdJTVBXgQ4XAAAGDklEQVR42u2bW0xTdxzHv6enLR6wtmKhtFxEBIpgCSKOeMGhqOgcC8wLyyJx
MXuaD0s0WUw2s+1hD3NbdiVZzG4YY8SZ0EkiRvGSjcUYjEUrrdiAAu6UMugOUG6ntGcPiJv0VGtL
20Ph9/jn/8/p7/P/3c+BqK6xcJjDIsIcl3kA8wDmAcxtEU9fOLg/AwBQXWPhXfdVpp+ft4DZYgEv
cqPerCUiAQhZZDYbNEYjZFYrnNHR6M3MRF9GBpwLFkQ2ADlNI/3qVcS1t4NwuSYXCQJymsa4TAZ7
amrkxgA5TWNVbS3i79//T3kA4DhE9/djUU9P5AZBimGQU18PimHmXhaIcjigbWyE3Grl30AQGFmy
BIMJCZEXBCmGgbaxEQmtrQDn2cS6JBIwycnozs/HUKQBWNzVhezz5yHr6QExXXmCgHXlSpi3b8f4
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jLW3ggKQ2NKCOIvFM9ITBIbi4mCsqAi5yYcUgPruXY8czxEE7KmpMO3cCUdcXNir0KC7gEdtr1LB
WF4eFn8PGQCSZSdvnyfdDarVglE+KACe5Ptbt3ibG7dYWEMo8UwqnnLzJpKbmyEZG+Pdw4lEPr+0
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myRh2Ls36P7OsqN42HEbv3x/CDf+1Pt0xuVywmbtgP7MZ/jt18+frPsFQG00IsZu91jv1Wp9+jbP
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AGzWDp/OSKMobNq2HwAwPj4cWAyI6evj9X370qWhD2JiqY9uM4Y/rpwCAGiz1wUGYFipfAoCRxB4
lJ8f1BcY/xfHkP2JH6/QbfA5gJKkBC+tL8frbxwJDICluBjaxkZQDAO3WAyrToeugoKgKz49sien
5mDPvqM+n3e5nGgzXYehuQEbS/b5D8Cq08Gq04U1f0ulFF6teBdyRfxzg+Ck8hP429aJc2e/QO2J
j+F0sijZfmB2fSpbXWPBVz/cxYF3voabc+H4NwfR+cDoW89CipGgWY43D3wCALhy4efA6oBwiUQS
hdWFr+C13YfhcjlxuuZDcBznVxyZlQCmpHhLFVTq5eh6YETT1dPP3e92u2CzduDUT+9P1jKJ6cEb
iYVCSLEEe6uO4ttjb0F/5hhy80t44wHfF68iEYmy3YdntwUAQFbOeuQVlGJs1IHaEx89cy9BiLBI
Hoe8glIc+uA0cnI3Tq7P//P0HJc5D+BfQqRAcLJ2SUgAAAAASUVORK5CYII=" />
</div>
<hr />
<form>
<textarea id="vs" rows="10" cols="80">
#version 110
attribute vec3 position;
attribute vec2 coord;
varying vec2 texCoord;
void main(void) {
gl_Position = vec4(position, 1.0);
texCoord = coord;
}
</textarea>
<button type="button" onclick="updateShaders()">update</button>
<hr />
<textarea id="fs" rows="10" cols="80">
#version 110
uniform sampler2D texture0;
varying vec2 texCoord;
void main(void) {
gl_FragColor = texture2D(texture0, texCoord);
//gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
}
</textarea>
<button type="button" onclick="updateShaders()">update</button>
<hr />
</form>
</body>
</html>
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